The practice of evidence-based medicine requires efficient, easy to use, standardized outcome assessment protocols and instruments with known reliability and validity. At present, there exist no protocols and instruments that are practical for clinical use on a daily basis to assess the benefit of cochlear implants (CIs). The need for such protocols and instruments is increased by the recent advent of bilateral CIs, since the assessment of binaural benefits is time consuming and requires special testing facilities. The primary purpose of the Phase II research is to complete the development, validation, implementation, and norming of a practical assessment protocol and instrument that can quickly provide a standardized outcome assessment of patients with either monolateral or bilateral CIs in the clinician's office, without the need for a sound room or other audiological instrumentation. The protocol will be implemented in a prototype, computerized instrument to be developed during Phase II. A primary focus will be on binaural assessment of patients with bilateral CIs of all types; however, an assessment protocol for monolateral implants of all types will also be developed. The prototype instrument will allow the assessment protocol to be performed either in the sound field with loudspeakers (SF tests) or by direct connection (DC tests) of the instrument's outputs to the auxiliary input(s) of the patient's CI(s). When used for direct-connect testing, the computerized instrument will preprocess the outputs to create monoaurally or binaurally appropriate test signals for each outcome measure. The instrument will be designed to interface with all commercially available CI processors and will utilize novel digital signal processing techniques to create the test signals. The proposed instrument will have a significant impact in the CI field because it will enable the practice of evidence-based medicine in selecting CI candidates and following the outcome of cochlear implantation. It will also enable further research into the functional abilities of CI patients and facilitate further improvement in CI technology. Individual CI patients will be evaluated more quickly and more accurately. [unreadable] [unreadable] [unreadable]